Jack Sabre has always been a good cop, a Denver detective who has every reason to be the "nicest guy on the force." His wife, Maria, is the love of his life. She regularly volunteers at a local mission for the homeless, but her charity work brings her into contact with greedy men on the dark side of the city, and she ends up dead. Murdered. Brutally. But who killed her and why? Jack thinks he knows, and with the department dragging its feet on the investigation, he goes after the killer himself, earning him the nickname "Black Jack." But the line between justice and revenge is thin and brittle, and when crossing that line backfires on Jack, people get killed, both good people and bad.